Water distribution systems for multi-story buildings typically comprise various arrangements of water supply and returns. Multi-story buildings introduce challenges including minimizing redundant piping and providing some form of pressure control from floor to floor where hydrostatic head varies, yet pressure for domestic purposes should be relatively constant.
As set forth in U.S. Pat. No. 5,183,102 to Clark, the entirety of which is incorporated herein by reference, an improvement in efficiency in piping runs was suggested using existing sprinkler systems and domestic hot water systems to double as cooling and heating systems. This system avoids piping an independent supply of chilled water through a first dedicated piping system that circulates the chilled water throughout the building and avoids piping an independent heating system and supply of hot water through a separate second dedicated piping system for circulation throughout the building.
Traditionally, room-by-room heating, and air conditioning systems in large buildings have been what are known in the art as four-pipe fan-coil systems; two pipes for cooling water flow, and two for heating water flow. Individual fan-coil units placed at various locations throughout the building provide for zonal temperature control. Heating or cooling is provided by having the fan circulate air over a coil that is accessing either the hot-water or the chilled-water piping system, respectively. As was recognized by Clark, while the four-pipe fan-coil system provides zonal temperature control, economy of operation, low maintenance, and minimum noise, the relatively high cost of constructing the dedicated hot and chilled-water piping systems had reduced their popularity.
Clark utilized a watercooler integrated into the fire sprinkler piping system of a building. The watercooler, along with a chilled-water pump, circulates chilled water throughout the fire sprinkler piping system. In addition, water circulating in the domestic hot-water piping system is accessed for heating purposes.
While Clark discussed implementation to multi-story buildings, there is no solution offered which recognizes variations in hydraulic pressure as water is delivered from the lowest floor to the highest floor, particularly when considering domestic water requirements and the desirability of experiencing consistent water pressure. To date, the Clark system has been applied to low buildings and each floor is supplied with independent risers from the main floor to each higher floor at pressures of about 40 to 74 psig.
In a 24 storey building the pressure at the lowest floor may be about 130 psig so as to maintain 40 psig at the roof where the hydraulic head is at its minimum. To supply a 72 storey building from a single riser would result in pressures at the lowest floor at about 250 psi. However, it is unacceptable to apply 250 psi or even 130 psig water for domestic use. Further, higher pressure in the domestic hot water system will ensure return flow to the boilers but the pressure is too high for domestic purposes.
Shortcomings in the known combination sprinkler and domestic hot water systems have resulted in limited acceptance of the technology even after all of this time. Applicant addresses these shortcomings.